Boxing in south jersey?

Only two I can think of off the top of my head are Daddis Fight Camps in Cherry Hill/Hamilton and Goss and Goss in Trenton (depending on where you're from, you may not consider Hamilton/Trenton to be South Jersey) Daddis is an MMA gym. If you're hard core and looking for a real, old school boxing gym, Goss is your place. Hard Knocks in Glassboro used to be good, but I don't think it's been open for quite a while.
Depends what your goals are. Its hard finding quality places anywhere, but if your goal is to fight, you're better off going to Philly.